Plant analysis using near infrared reflectance spectroscopy: the potential and the limitations

International Standards Committees have formally accepted methods using near infrared spectroscopy for the analysis of protein, moisture and hardness in grains, and protein, acid detergent fibre and moisture in forages. In addition, near infrared spectroscopy is used world-wide for the routine analysis of many constituents in various tissues of many plant species. The reasons for near infrared spectroscopy being adopted as the preferred analytical method in many laboratories include: minimal sample preparation is needed, analysis time is short, it is cost effective to analyse a single sample or large batches of samples, several constituents can be determined simultaneously, the samples are not destroyed during analysis, neither a laboratory nor a skilled operator are required for routine analyses, the use of hazardous chemical reagents is eliminated, and, depending on the method, the results are usually more precise and can be more accurate than, as accurate as, or of acceptable accuracy, when compared with the method usually employed. It is the responsibility of the analyst to choose the most appropriate analytical technique and to follow standard procedures in order to obtain accurate and precise results from routine analysis. This paper summarises some of the applications of near infrared spectroscopy which are being used to analyse plant samples and lists some of the criteria which can be used to decide if near infrared spectroscopy is the most appropriate technique.